1. Field of the Invention
The present invention relates, in general, to door hinge structures for passenger airbags and, more particularly, to a door hinge structure for passenger airbags, which can normally execute a designated behavior of the airbag without breaking when an airbag door opens, when airbag cushions of various kinds of airbag modules having different explosive pressures expand.
2. Description of Related Art
Generally, a front passenger airbag of a car includes an airbag module installed in a crash pad and, and when a car collision occurs, an airbag door opens and an airbag cushion expands to protect a passenger from impact stemming from the collision.
An invisible airbag door provided in a crash pad is integrated with the crash pad into a single structure for improving the appearance of the crash pad. Therefore, a door line of the invisible airbag door is not visible from the outside, but a skin cut part is formed in the inner surface of a skin layer at a predetermined location such that it allows a panel of the crash pad to be easily opened when the airbag door opens.
In the invisible airbag door, an airbag door line is formed in the crash pad by forming a thin and weak part in the crash pad in such a way that, when an airbag cushion expands, the airbag door can open along the thin airbag door line and the airbag cushion can expand through the open airbag door. In the related art, the airbag door line of the invisible airbag door was formed by injection-molding the crash pad in such a way that some of the crash pad becomes thinner along a designated airbag cushion expanding line or is formed by forming a micro-groove along the designated airbag cushion expanding line using a laser beam after the crash pad has been injection-molded.
FIG. 1 is a sectional view illustrating a conventional door hinge structure for a passenger airbag. As shown in FIG. 1, a crash pad 1 is provided in front of a front passenger seat inside a passenger compartment and an airbag module 2 is installed inside the crash pad 1 at a location spaced apart from the crash pad 1 by a predetermined distance.
The airbag module 2 is configured such that an airbag cushion can expand in response to an impact generated by a car collision. As shown in FIG. 1, an airbag door 10 having a hinge unit 11 is provided in the inner surface of the crash pad 1 at a location facing the airbag module 2.
In a typical airbag, the airbag door is welded to the inner surface of the crash pad while an edge of the airbag door opposed to the hinge unit is cut so that, when the airbag cushion expands, the airbag door is pushed and rotated outwards around the hinge unit, thus opening.
However, the airbag door 10 having the structure shown in FIG. 1 is integrated with the crash pad 1 into a single structure using a single material and is typically used with a low explosive pressure airbag, such as the depowered airbag typically used in Korea or Europe. Thus, the airbag door 10 having the structure shown in FIG. 1 is problematic in that, when the airbag door 10 is used with a high explosive pressure airbag, such as an advanced airbag typically used in North America, the airbag door 10 may fail to behave normally as designated, but may break the hinge unit when the airbag cushion expands.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.